diff --git a/Sources/Brave/Frontend/Browser/Tab.swift b/Sources/Brave/Frontend/Browser/Tab.swift
index 330f5406fb62..f669fb93fdf9 100644
--- a/Sources/Brave/Frontend/Browser/Tab.swift
+++ b/Sources/Brave/Frontend/Browser/Tab.swift
@@ -715,6 +715,13 @@ class Tab: NSObject {
 
   func updateUserAgent(_ webView: WKWebView, newURL: URL) {
     guard let baseDomain = newURL.baseDomain else { return }
+    
+    let screenWidth = webView.currentScene?.screen.bounds.width ?? webView.bounds.size.width
+    if webView.traitCollection.horizontalSizeClass == .compact && (webView.bounds.size.width < screenWidth / 2.0) {
+      let desktopMode = userAgentOverrides[baseDomain] == true
+      webView.customUserAgent = desktopMode ? UserAgent.desktop : UserAgent.mobile
+      return
+    }
 
     let desktopMode = userAgentOverrides[baseDomain] ?? UserAgent.shouldUseDesktopMode
     webView.customUserAgent = desktopMode ? UserAgent.desktop : UserAgent.mobile